I. Field of the Invention
This invention relates generally to a safety device for power tools and more specifically to a switch actuating mechanism which when appropriately mounted on a power tool stand, allows the operator to turn on the tool's drive motor by a conscious depression of a relatively small sized push button, but permits the motor to be turned off by depression of a relatively broad surface member by a body part other than the hands of the operator whereby there is no need for the operator to take his eyes or hands off of the work and the cutting or abrading tool.
II. Description of the Prior Art
In my earlier U.S. Pat. Nos. 3,312,799 and 4,166,202 there are described various forms of switch actuating mechanisms comprising an "on/off" or momentary type toggle switchs which are adapted to be operatively connected in circuit with an electrical motor for controlling the flow of current thereto. Like the present invention, each of those earlier switch actuating mechanisms included a broad surface member of one type or another pivotally mounted in proximity to the operator's station and this member is mechanically linked to the on/off lever of the toggle switch. Furthermore, in my earlier arrangements described in the aforereferenced patents, a latch and wire bail arrangement is provided which must be appropriately manipulated in a conscious manner before the toggle switch can be moved to its "on" position. As such, the inadvertent turning on of the power to the drive motor is obviated. Once the motor of the tool is turned on, it may be turned off by bumping the broad surface panel member with one or more parts of the operator's anatomy other than his hands and this operation may be accomplished without having to glance away from the working surface of the tool being used. This, of course, leads to greater safety by preventing accidental or inadvertent movement of the workpiece or hands into a position where they may be injured by the tool.
While the earlier arrangements described were altogether satisfactory in their operation, the fabrication of the devices tended to be overly costly to manufacture because of the number of parts involved, making it somewhat difficult to market at a price commensurate with the cost of the tool on which the safety mechanism was adapted to be used.
The instant invention is considered to be an improvement over my two prior inventions. It provides a switch actuating mechanism of the general type described but is designed to be substantially less complicated in terms of the number of parts and their assembly into a completed article. This has been done without compromising the element of safety for which the earlier devices were designed. Furthermore, the present invention incorporates certain of the novel features of my earlier designs resulting in what is considered to be a significant advance in the state-of-the-art.